Humminbird Side Imaging Forums
Side Imaging Forums => 997c SI, 998c SI & 999ci HD SI => Topic started by: j_wireman on March 19, 2015, 02:21:07 PM
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Finally got to get out with my 998 fir the first time today. everything seems to work, but, I have something going on with the right side and down image. I took some screenshots. The problem seems to vary with the speed of the boat, the slower I move, the worse the problem is. The transducer is mounted on the jackplate with nothing below or beside it. Any ideas?
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Transducer install pics
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We have seen this before j_wireman. It’s a classic example of Si sonar being reflected off of the inside of the jackplate. A few ways to get rid of it are to either move the transducer or block off the bottom of the jackplate [ I can’t remember what they call those… someone help me out here guys I’m having one of those moments! ]. I would cover the bottom of the jackplate.
Its gets worse the slower you go because at higher speeds there is aerated water (or no water) getting in between the transducer and the other side of the jackplate, thus decreasing the amount of reflected right Si sonar back to the transducer. If you would set your SI Range to, say 20 feet, it would look even worse!
Forgot to add (see, I forgot again!) that is shows up in the Di sonar because that is derived from the Si sonar.
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Thanks for the response. That's pretty much what i thought. I actually tried to adjust the angle of the ducer while in he water. As I ran my hand down the inside of the jackplate, I could see on the screen the noise was reduced. I suppose my hand / arm reflected or absorbed some of the signal being reflected. I will try to block off the space inside the jackplate and try again. Otherwise, I like what I have seen so far.
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Hole shot plate. That was what i couldn't remember yesterday. If covers the bottom of the jackplate and helps keep water from flowing into it for a better (faster) hole shot.